Comment by rajlego

Something that really bothers me about coffee culture is that coffee is seen as a solution to being tired when really all it is is just an alertness booster. The main neurological cause of sleepiness is the brain’s desire to do memory optimization which can only happen by sleeping at the right time. Correct timing is really important and it seems to me like you have DSPS (delayed sleep phase syndrome). Most people’s circadian rhythms are a bit longer than 24 hours (usually between 24.5-25.5 hours) though external signals like exercise or bright light in the morning reset it to being closer to 24. If you have DSPS, yours isn’t reset well (you can try the aformtentioned morning bright light and exercise to change this) and you have a tendency to wake up later and later each day. The problem is that if you have to wake up at 7 every day and you think you need 9 hours of sleep you’ll try to sleep at 10 to get enough which backfires. The reason it can backfire is that for good sleep you need both strong homeostatic sleep signals (tiredness from thinking a lot or doing a lot of effort in the day) and circadian (sleepiness goes and comes cyclically). If you sleep at 10 and have DSPS, even if your homeostatic signals sleep, it is likely that your circadian isn’t which means you end up tossing and turning throughout the night. If you slept maybe an hour later you’d get full circadian and homeostatic sleepiness giving you good quality sleep but if you have to wake up at 7 you have to cut short sleep with an alarm clock which isn’t great since your brain can’t complete all the memory optimization it wants. I would say though that sleeping later more restfully for shorter will do you better than sleeping earlier restlessly. (Sorry for the essay, sleep is something I care about a lot. I hope this was a little helpful.)